Permanent hair waving neutralization by monopersulfate



FIP8309 United States Patent 2,774,355 Patented Dec. 18, 1956 or setting step of permanent waving. Another object is 2774 355 provision of an oxidizing agent for permanent waving PERMANENT HAIR WAVING NEUTRALIZATION which is adapted for use in the home by an amateur beauty stylist. Another object of the invention is pro- BY MONOPERSULFATE vision of a novel oxidizing agent which is naturally acidic in reaction and which does not damage hair to ggfi g' i gax g g gmhy g i fi 'figf fg f bgifg whic h it is applied. A further object is provision of an corporation of Delaware oxidizing agent for permanent waving WhlCh reacts rapidly with the sulfhydryl groups of the hair and without No Drawing. Application March 23, 1955, 10 leaving any bad odor.

Senal The above-mentioned and still further objectives are 3 Claims (CL 2 7 achieved in accordance with this invention by a permanent waving process departing from those in customary use only in employing an aqueous solution of an alkali This'invention relates to improvements in the treat- 15 metal monopersulfate in the final or wave-setting step. ment of substances containing keratin, such as hair and Thus, hair may first be treated with thioglycolic or wool. It is particularly concerned with improvements formamidine sulfinic acid, shaped as desired, rinsed if in the application of a set to hair during an otherwise subnecessary and finally set in place by means of the alkali stantially conventional permanent waving process. metal monopersulfate.

It is customary to treat a susbtance which contains The preferred monopersulfates of this invention are keratin, human hair especially, with a chemical agent to those of sodium and potassium, NaHSOs and KHSOs. relax the individual fibers, then to bend the material They may be directly employed at the natural pH of physically into a new and desired shape and finally to set their aqueous solution, i. e., pH 2 or 3, and use of the it permanently in the new shape by means of a second compounds at their natural pH represents the preferred chemical treatment. embodiment of the invention. It is not essential, how- The compound employed in the relaxation treatment ever, that the monopersulfates be used only at these is an alkaline reducing agent which converts the disulfide acidities. Higher pH values are effective although they groups in the keratin to sulfhydryl groups and thereby may accelerate the decomposition of the oxidizing agent. breaks peptide or other chains joined by disulfide link- A pH of 6 or 7 or even higher can be obtained readily ages. Many reducing agents are known which relax by adding a buffer compound such as sodium phosphate keratin-containing fibers, including formamidine sulfinic or silicate to the solution or, in predetermined quantity, acid, thioglycolic acid, sodium sulfide, sodium hydroto the dry salt. sulfide, cysteine hydrochloride, sodium hypophosphite, The solutions utilized may vary in concentration most sodium thiosulfate, sodium hydrosulfite, sodium didesirably from about 500 p. p. m. to 2000 p. p. m. of thionate, thiolactic acid, thioglycerol, ii-mercapto-ethanol active oxygen but higher concentrations may be used and others. These compounds of the prior art may be if corresponding care is taken not to damage the hair used as heretofore in a first or reducing step of the intreated. Lower concentrations may also be used but stant process. Thioglycolic and formamidine sulfinic may require time to accomplish their intended purpose. acids, however, are among the most satisfactory for use The active oxygen of a monopersulfate, as used in this invention. throughout this specification, is the oxygen in the molecule It will readily be understood that the intermediate or in excess of that required to form the corresponding shaping step also remains unchanged over the prior bisulfate. For potassium monopersulfate it may be exart. This step may consist of a very simple process such pressed as a percentage from the equation for the decomas bending or twisting separate locks of hair into a desired position of the compound, contour.

Heretofore a multiplicity of compounds have been KHSO5+KHSO4+[O] used in the setting or oxidizing step of the waving procm the followmg manner: ess. Such compounds should, in general, cause little Wt, f [O] damage to the hair and should take effect rapidly. Pref- Percent active oxygen=mx 100 erably they should, in addition, be acidic in nature to neutralize the alkaline reducing agent. Hydrogen per- The symbol [0] represents the oxygen produced by the oxide, alkali metal bromates and sodium perborate are decomposition of the monopersulfate. examples of oxidizing agents utilized previously to this The temperature of application is not sharply critical. end. Ammonium dipersulfate has also been suggested A temperature between ambient, ca. 20'' C., and about as a suitable agent. 40 C. is preferred. Higher temperatures can be em- Each of the oxidizing agents named sufiers from varployed if desired but are unnecessary. Lower temperaious defects detracting from its utility. Hydrogen pertures can also be used but may be uncomfortable to the oxide, for example, must be slightly acidified before human subject being treated. use and tends so strongly to damage or bleach the hair The time of contact between the hair and the monothat it has found only minor utility in this field and is persulfate solution also lacks sharp criticality. This somewhat restricted to use by the professional beauty time should, however, be kept to a minimum to prevent stylist. The alkali metal bromates, while otherwise damage to the hair. A time comparable to that of a quick satisfactory, possess such oral toxicity that they are at shampoo or rinse is satisfactory and is preferred. Total a commercial disadvantage, especially when used in the contact time should actually not exceed five minutes, home by the amateur beautician. Sodium perborate is with an even shorter period, two or three minutes, being at a disadvantage because of its high alkalinity and low preferred. Contact periods slightly longer than five minsolubility. Ammonium dipersulfate is too slow in oxidizutes can be tolerated but damage to the hair increases proing reaction for practicable utility. Several other oxidizgressively as the period lengthens. ing agents which have been suggested at various times A preferred embodiment of the invention, according to possess odors of a distinctly disagreeable character. the principles set forth above, may now be described:

A primary object of the present invention is, therefore, provision of a novel oxidizing agent for use in the last Hair is soaked with an aqueous solution of thioglycolic or formamidine sulfinic acid adjusted to pH 8-9 with ammonia and is curled on a plastic curler. It is then sequentially rinsed in warm water, allowed to stand for a short time and treated with an aqueous solution containing potassium monopersulfate. The curl is then rinsed rapidly and thoroughly, undone and finally air dried. The result is permanently curled hair which has lost very little of its tensile strength.

The advantages obtained by use of monopersulfates generally parallel the objectives of the invention. Thus, the low pH of these compounds eliminates the necessity for utilizing a two-component system containing both an oxidizing agent and an acid. The monopersulfates are, furthermore, strong oxidizing agents which react rapidly without unduly damaging the hair. In addition, the relative stability, high solubility and non-toxicity of the monopersulfates eliminates difiiculties found in agents of the prior art.

There follow some examples which illustrate the prac tice of the invention in detail. Unless otherwise noted, the temperatures of all applications are ambient.

Example 1 This example illustrates the use of a solution of potassium monopersulfate in the process of the invention.

A lock of hair was saturated with an aqueous solution adjusted to pH 8-9 with ammonia and containing 4.7% thioglycolic acid. The lock was curled on a plastic curler, allowed to stand on the curler for 15 minutes and then rinsed, in position, with hot water for 2 minutes. The curl was maintained on the curler for an additional 30 minutes and was then saturated with a solution containing 1500 p. p. m. of active oxygen as potassium monopersulfate. The curl was unwound, resaturated with the potassium monopersulfate solution, rinsed thoroughly with warm water and finally dried in air. The hair was found to be well curled and to have lost only about 6% in tensile strength.

Example 2 This example illustrates the use of a potassium mono persulfate somewhat less concentrated than that used above.

As in the first example a lock of hair was saturated with an aqueous solution containing ammonia and 4.7% thioglycolic acid, was allowed to stand curled on a plastic curler for 15 minutes and was then rinsed with hot water for 2 minutes. After standing for 15 more minutes, the curl was saturated with a solution containing 750 p. p. m. of active oxygen as potassium monopersul-fate. The curl was unwound, resaturated with the above described neutralizer, rinsed thoroughly with warm water and finally dried in air. Results were the same as in Example 1: the hair was well curled and had lost only about 6% of its tensile strength.

Having described my invention, I claim:

1. The process of restoring disulfide linkages to hair in which the linkages have been disrupted by reduction comprising treating said hair with an aqueous solution con taining between about 500 and 2000 p. p. m. of active oxygen bound in the form of the monopersulfate of an alkali metal, said treatment being carried out at a pH of about 2-3 and a temperature of about 20-40 C. for not more than about 5 minute-s.

2. The process of claim 1 in which the alkali metal is potassium.

3. The process of claim 1 in which the alkali metal is sodium.

References Cited the file of this patent UNITED STATES PATENTS 2,077,103 Franz Apr. 13, 1937 2,334,126 Reichert Nov. 9, 1943 2,362,401 Reichert Nov. 7, 1944 2,426,142 Campbell Aug. 19, 1947 FOREIGN PATENTS 561,521 Germany Oct. 15, 1932 453,700 Great Britain 1936 1,003,963 France Nov. 21, 1951 OTHER REFERENCES 

1. THE PROCESS OF RESTORING DISULFIDE LINKAGES TO HAIR IN WHICH THE LINKAGES HAVE BEEN DISRUPTED BY REDUCTION COMPRISING TREATING SAID HAIR WITH AN AQUEOUS SOLUTION CONTAINING BETWEEN ABOUT 500 AND 2000 P.P.M. OF ACTIVE OXYGEN BOUND IN THE FORM OF THE MONOPERSULFATE OF AN ALKALI METAL, SAID TREATMENT BEING CARRIED OUT AT A PH OF ABOUT 2-3 AND A TEMPERATURE OF ABOUT 20-40* C. FOR NOT MORE THAN ABOUT 5 MINUTES. 